Synthetic Turing protocells: vesicle self-reproduction through symmetry-breaking instabilities

The reproduction of a living cell requires a repeatable set of chemical events to be properly coordinated. Such events define a replication cycle, coupling the growth and shape change of the cell membrane with internal metabolic reactions. Although the logic of such process is determined by potentially simple physico-chemical laws, the modeling of a full, self-maintained cell cycle is not trivial. Here we present a novel approach to the problem which makes use of so called symmetry breaking instabilities as the engine of cell growth and division. It is shown that the process occurs as a consequence of the breaking of spatial symmetry and provides a reliable mechanism of vesicle growth and reproduction. Our model opens the possibility of a synthetic protocell lacking information but displaying self-reproduction under a very simple set of chemical reactions

Graph Partitioning using Quantum Annealing on the D-Wave System

In this work, we explore graph partitioning (GP) using quantum annealing on the D-Wave 2X machine. Motivated by a recently proposed graph-based electronic structure theory applied to quantum molecular dynamics (QMD) simulations, graph partitioning is used for reducing the calculation of the density matrix into smaller subsystems rendering the calculation more computationally efficient. Unconstrained graph partitioning as community clustering based on the modularity metric can be naturally mapped into the Hamiltonian of the quantum annealer. On the other hand, when constraints are imposed for partitioning into equal parts and minimizing the number of cut edges between parts, a quadratic unconstrained binary optimization (QUBO) reformulation is required. This reformulation may employ the graph complement to fit the problem in the Chimera graph of the quantum annealer. Partitioning into 2 parts, 2^N parts recursively, and k parts concurrently are demonstrated with benchmark graphs, random graphs, and small material system density matrix based graphs. Results for graph partitioning using quantum and hybrid classical-quantum approaches are shown to equal or out-perform current "state of the art" methods

Negative ions formed in N₂/CH₄/Ar discharge – a simulation of Titan's atmosphere chemistry

The formation of negative ions produced in a negative point-to-plane corona discharge fed by a Ar/N2//CH4/ gas mixture has been studied using mass spectrometry. The measurements were carried out in flowing regime at ambient temperature and a reduced pressure of 460 mbar. The CN ? anion has been found to be the most dominant negative ion in the discharge and is believed to be the precursor of heavier negative ions such as C3/N ? and C5/N ? . The most likely pathway for the formation of such molecular anions is H-loss dissociative electron attachment to HCN, H3/CN and H5/CN formed in the discharge. These same anions have been detected in Titan's atmosphere and the present experiments may provide some novel insights into the chemical and physical mechanisms prevalent in Titan's atmosphere and hence assist in the interpretation of results from the Cassini Huygens space mission

Non equilibrium inertial dynamics of colloidal systems

We consider the properties of a one dimensional fluid of brownian inertial hard-core particles, whose microscopic dynamics is partially damped by a heat-bath. Direct interactions among the particles are represented as binary, instantaneous elastic collisions. Collisions with the heath bath are accounted for by a Fokker-Planck collision operator, whereas direct collisions among the particles are treated by a well known method of kinetic theory, the Revised Enskog Theory. By means of a time multiple time-scale method we derive the evolution equation for the average density. Remarkably, for large values of the friction parameter and/or of the mass of the particles we obtain the same equation as the one derived within the dynamic density functional theory (DDF). In addition, at moderate values of the friction constant, the present method allows to study the inertial effects not accounted for by DDF method. Finally, a numerical test of these corrections is provided.Comment: 13 pages+ 3 Postscript figure

Effect of heating oxyhemoglobin and methemoglobin on microsomes oxidation.

Hemoglobin (Hb) has been proposed to be a major pro-oxidant in raw and cooked meats. To understand the mechanisms and differentiate between the pro-oxidant and antioxidant potential of oxyhemoglobin (OxyHb) and methemoglobin (MetHb), their pro-oxidant activity, protein solubility, radical scavenging capacity, iron content and contribution of non-chelatable iron on lipid oxidation were determined as a function of thermal treatments. The ability of native OxyHb and MetHb to promote lipid oxidation was similar and higher than their corresponding OxyHb or MetHb heated at 68 and 90 degrees C but not different from those at 45 degrees C. The pro-oxidant activity of MetHb heated at 68 and 90 degrees C were similar whereas the pro-oxidant activity of OxyHb heated at 68 degrees C was higher than that heated at 90 degrees C. The decreased pro-oxidant activity of heat-denatured Hb was associated with a decrease in the solubility of heme iron while free iron showed little impact on the lipid oxidation

The Use of CytoSorb Therapy in Critically Ill COVID-19 Patients: Review of the Rationale and Current Clinical Experiences

Coronavirus SARS-CoV-2; COVID-19; 2019-nCoV; Teràpia CytoSorbCoronavirus SARS-CoV-2; COVID-19; 2019-nCoV; Terapia; CytoSorbCoronavirus SARS-CoV-2; COVID-19; 2019-nCoV; CytoSorb; TherapyThe COVID-19 pandemic has led to the biggest global health crisis of our lifetime. There is accumulating evidence that a substantial number of critically ill COVID-19 patients exhibit a dysregulated host response manifesting as cytokine storm or cytokine release syndrome, which in turn contributes to the high observed rates of mortality. Just as in other hyperinflammatory conditions, extracorporeal cytokine removal may have potential beneficial effects in this subgroup of COVID-19 patients. The CytoSorb blood purification device is the most extensively investigated cytokine removal platform with considerable evidence suggesting that early intervention can provide rapid hemodynamic stabilization and improvement in vital organ functions. The purpose of this review is to provide an overview of the pathophysiological background of hyperinflammation in COVID-19 and to summarize the currently available evidence on the effects of hemoadsorption in these patients

Effects of footwear variations on three-dimensional kinematics and tibial accelerations of specific movements in American football

American football is associated with a high rate of non-contact chronic injuries. Players are able to select from both high and low cut footwear. The aim of the current investigation was to examine the influence of high and low cut American football specific footwear on tibial accelerations and three-dimensional (3D) kinematics during three sport specific movements. Twelve male American football players performed three movements, run, cut and vertical jump whilst wearing both low and high cut footwear. 3D kinematics of the lower extremities were measured using an eight-camera motion analysis system alongside tibial acceleration parameters which were obtained using a shank mounted accelerometer. Tibial acceleration and 3D kinematic differences between the different footwear were examined using either repeated measures or Friedman’s ANOVA. Tibial accelerations were significantly greater in the low cut footwear in comparison to the high cut footwear for the run and cut movements. In addition, peak ankle eversion and tibial internal rotation parameters were shown to be significantly greater in the low cut footwear in the running and cutting movement conditions. The current study indicates that the utilization of low cut American football footwear for training/performance may place American footballers at increased risk from chronic injuries

Emergence of Zipf's Law in the Evolution of Communication

Zipf's law seems to be ubiquitous in human languages and appears to be a universal property of complex communicating systems. Following the early proposal made by Zipf concerning the presence of a tension between the efforts of speaker and hearer in a communication system, we introduce evolution by means of a variational approach to the problem based on Kullback's Minimum Discrimination of Information Principle. Therefore, using a formalism fully embedded in the framework of information theory, we demonstrate that Zipf's law is the only expected outcome of an evolving, communicative system under a rigorous definition of the communicative tension described by Zipf.Comment: 7 pages, 2 figure

Two sequential outbreaks caused by multidrug-resistant Acinetobacter baumannii isolates producing OXA-58 or OXA-72 oxacillinase in an intensive care unit in France

International audienc